FIG. 1 shows a prior art "chopstick" type curler 10 used in spiral permanent hair waving, which is typically performed by professional hair stylists. Chopstick curler 10 is characterized by a pair of substantially smooth slightly tapered rods 12a and 12b that are interconnected at their respective narrow ends 14a and 14b by a flexible circular loop 16.
A base end of a patron's lock or strand of hair is slid between rods 12a and 12b and past a releasable opening 18 in circular loop 16 formed by ends 14a and 14b. The strand of hair is then wrapped around a selected one of the rods 12a and 12b along a spiral path 20 (shown in phantom around rod 12a). The strand is nominally held in place by wrapping a rubber band (not shown) under tension around the distal ends 22a and 22b of respective rods 12a and 12b. The hair stylist then applies a permanent wave chemical or solution to the strand of hair in a manner known to those skilled in the art.
Although it is commonly available, chopstick curler 10 suffers from at least three major disadvantages. First, chopstick curler 10 is relatively uncomfortable for the patron because circular loop 16 tangentially contacts the patron's head. Since the strand of hair is typically wrapped around the curler relatively tightly, an uncomfortable amount of pressure can be exerted against a relatively small region of the patron's head.
Second, chopstick curler 10 is relatively difficult to use because the hair stylist must pass the patron's strand of hair between rods 12a and 12b for each revolution of the strand around the selected rod, thereby requiring a great deal of patience or skill on the part of the hair stylist. Finally, the substantially smooth nature of rods 12a and 12b allows the strand of hair to slide along them even after distal ends 22a and 22b are secured with a rubber band. Since the appearance of a spiral-type permanent hair wave is dependent upon the pitch of the spiral path of the hair along the curler, slippage of the hair can change the pitch of the spiral path and produce undesired nonuniformities in the appearance of the permanent hair wave.